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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network104.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
104.0.0.0
Broadcast address
104.127.255.255
First usable
104.0.0.1
Last usable
104.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 68000000 · Integer 1744830464 to 1753219071
Reverse DNS zones
0.104.in-addr.arpa
1.104.in-addr.arpa
2.104.in-addr.arpa
3.104.in-addr.arpa
4.104.in-addr.arpa
5.104.in-addr.arpa
6.104.in-addr.arpa
7.104.in-addr.arpa
8.104.in-addr.arpa
9.104.in-addr.arpa
10.104.in-addr.arpa
11.104.in-addr.arpa
12.104.in-addr.arpa
13.104.in-addr.arpa
14.104.in-addr.arpa
15.104.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01101000.00000000.00000000.00000000104.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network01101000.00000000.00000000.00000000104.0.0.0
Broadcast01101000.01111111.11111111.11111111104.127.255.255
Split into smaller subnets/20
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

104.0.0.0/9 makes 2,048 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1104.0.0.0/20104.0.0.1 to 104.0.15.254104.0.15.2554,094
2104.0.16.0/20104.0.16.1 to 104.0.31.254104.0.31.2554,094
3104.0.32.0/20104.0.32.1 to 104.0.47.254104.0.47.2554,094
4104.0.48.0/20104.0.48.1 to 104.0.63.254104.0.63.2554,094
5104.0.64.0/20104.0.64.1 to 104.0.79.254104.0.79.2554,094
6104.0.80.0/20104.0.80.1 to 104.0.95.254104.0.95.2554,094
7104.0.96.0/20104.0.96.1 to 104.0.111.254104.0.111.2554,094
8104.0.112.0/20104.0.112.1 to 104.0.127.254104.0.127.2554,094
9104.0.128.0/20104.0.128.1 to 104.0.143.254104.0.143.2554,094
10104.0.144.0/20104.0.144.1 to 104.0.159.254104.0.159.2554,094
11104.0.160.0/20104.0.160.1 to 104.0.175.254104.0.175.2554,094
12104.0.176.0/20104.0.176.1 to 104.0.191.254104.0.191.2554,094
13104.0.192.0/20104.0.192.1 to 104.0.207.254104.0.207.2554,094
14104.0.208.0/20104.0.208.1 to 104.0.223.254104.0.223.2554,094
15104.0.224.0/20104.0.224.1 to 104.0.239.254104.0.239.2554,094
16104.0.240.0/20104.0.240.1 to 104.0.255.254104.0.255.2554,094
17104.1.0.0/20104.1.0.1 to 104.1.15.254104.1.15.2554,094
18104.1.16.0/20104.1.16.1 to 104.1.31.254104.1.31.2554,094
19104.1.32.0/20104.1.32.1 to 104.1.47.254104.1.47.2554,094
20104.1.48.0/20104.1.48.1 to 104.1.63.254104.1.63.2554,094
21104.1.64.0/20104.1.64.1 to 104.1.79.254104.1.79.2554,094
22104.1.80.0/20104.1.80.1 to 104.1.95.254104.1.95.2554,094
23104.1.96.0/20104.1.96.1 to 104.1.111.254104.1.111.2554,094
24104.1.112.0/20104.1.112.1 to 104.1.127.254104.1.127.2554,094
25104.1.128.0/20104.1.128.1 to 104.1.143.254104.1.143.2554,094
26104.1.144.0/20104.1.144.1 to 104.1.159.254104.1.159.2554,094
27104.1.160.0/20104.1.160.1 to 104.1.175.254104.1.175.2554,094
28104.1.176.0/20104.1.176.1 to 104.1.191.254104.1.191.2554,094
29104.1.192.0/20104.1.192.1 to 104.1.207.254104.1.207.2554,094
30104.1.208.0/20104.1.208.1 to 104.1.223.254104.1.223.2554,094
31104.1.224.0/20104.1.224.1 to 104.1.239.254104.1.239.2554,094
32104.1.240.0/20104.1.240.1 to 104.1.255.254104.1.255.2554,094
33104.2.0.0/20104.2.0.1 to 104.2.15.254104.2.15.2554,094
34104.2.16.0/20104.2.16.1 to 104.2.31.254104.2.31.2554,094
35104.2.32.0/20104.2.32.1 to 104.2.47.254104.2.47.2554,094
36104.2.48.0/20104.2.48.1 to 104.2.63.254104.2.63.2554,094
37104.2.64.0/20104.2.64.1 to 104.2.79.254104.2.79.2554,094
38104.2.80.0/20104.2.80.1 to 104.2.95.254104.2.95.2554,094
39104.2.96.0/20104.2.96.1 to 104.2.111.254104.2.111.2554,094
40104.2.112.0/20104.2.112.1 to 104.2.127.254104.2.127.2554,094
41104.2.128.0/20104.2.128.1 to 104.2.143.254104.2.143.2554,094
42104.2.144.0/20104.2.144.1 to 104.2.159.254104.2.159.2554,094
43104.2.160.0/20104.2.160.1 to 104.2.175.254104.2.175.2554,094
44104.2.176.0/20104.2.176.1 to 104.2.191.254104.2.191.2554,094
45104.2.192.0/20104.2.192.1 to 104.2.207.254104.2.207.2554,094
46104.2.208.0/20104.2.208.1 to 104.2.223.254104.2.223.2554,094
47104.2.224.0/20104.2.224.1 to 104.2.239.254104.2.239.2554,094
48104.2.240.0/20104.2.240.1 to 104.2.255.254104.2.255.2554,094
49104.3.0.0/20104.3.0.1 to 104.3.15.254104.3.15.2554,094
50104.3.16.0/20104.3.16.1 to 104.3.31.254104.3.31.2554,094
51104.3.32.0/20104.3.32.1 to 104.3.47.254104.3.47.2554,094
52104.3.48.0/20104.3.48.1 to 104.3.63.254104.3.63.2554,094
53104.3.64.0/20104.3.64.1 to 104.3.79.254104.3.79.2554,094
54104.3.80.0/20104.3.80.1 to 104.3.95.254104.3.95.2554,094
55104.3.96.0/20104.3.96.1 to 104.3.111.254104.3.111.2554,094
56104.3.112.0/20104.3.112.1 to 104.3.127.254104.3.127.2554,094
57104.3.128.0/20104.3.128.1 to 104.3.143.254104.3.143.2554,094
58104.3.144.0/20104.3.144.1 to 104.3.159.254104.3.159.2554,094
59104.3.160.0/20104.3.160.1 to 104.3.175.254104.3.175.2554,094
60104.3.176.0/20104.3.176.1 to 104.3.191.254104.3.191.2554,094
61104.3.192.0/20104.3.192.1 to 104.3.207.254104.3.207.2554,094
62104.3.208.0/20104.3.208.1 to 104.3.223.254104.3.223.2554,094
63104.3.224.0/20104.3.224.1 to 104.3.239.254104.3.239.2554,094
64104.3.240.0/20104.3.240.1 to 104.3.255.254104.3.255.2554,094
65104.4.0.0/20104.4.0.1 to 104.4.15.254104.4.15.2554,094
66104.4.16.0/20104.4.16.1 to 104.4.31.254104.4.31.2554,094
67104.4.32.0/20104.4.32.1 to 104.4.47.254104.4.47.2554,094
68104.4.48.0/20104.4.48.1 to 104.4.63.254104.4.63.2554,094
69104.4.64.0/20104.4.64.1 to 104.4.79.254104.4.79.2554,094
70104.4.80.0/20104.4.80.1 to 104.4.95.254104.4.95.2554,094
71104.4.96.0/20104.4.96.1 to 104.4.111.254104.4.111.2554,094
72104.4.112.0/20104.4.112.1 to 104.4.127.254104.4.127.2554,094
73104.4.128.0/20104.4.128.1 to 104.4.143.254104.4.143.2554,094
74104.4.144.0/20104.4.144.1 to 104.4.159.254104.4.159.2554,094
75104.4.160.0/20104.4.160.1 to 104.4.175.254104.4.175.2554,094
76104.4.176.0/20104.4.176.1 to 104.4.191.254104.4.191.2554,094
77104.4.192.0/20104.4.192.1 to 104.4.207.254104.4.207.2554,094
78104.4.208.0/20104.4.208.1 to 104.4.223.254104.4.223.2554,094
79104.4.224.0/20104.4.224.1 to 104.4.239.254104.4.239.2554,094
80104.4.240.0/20104.4.240.1 to 104.4.255.254104.4.255.2554,094
81104.5.0.0/20104.5.0.1 to 104.5.15.254104.5.15.2554,094
82104.5.16.0/20104.5.16.1 to 104.5.31.254104.5.31.2554,094
83104.5.32.0/20104.5.32.1 to 104.5.47.254104.5.47.2554,094
84104.5.48.0/20104.5.48.1 to 104.5.63.254104.5.63.2554,094
85104.5.64.0/20104.5.64.1 to 104.5.79.254104.5.79.2554,094
86104.5.80.0/20104.5.80.1 to 104.5.95.254104.5.95.2554,094
87104.5.96.0/20104.5.96.1 to 104.5.111.254104.5.111.2554,094
88104.5.112.0/20104.5.112.1 to 104.5.127.254104.5.127.2554,094
89104.5.128.0/20104.5.128.1 to 104.5.143.254104.5.143.2554,094
90104.5.144.0/20104.5.144.1 to 104.5.159.254104.5.159.2554,094
91104.5.160.0/20104.5.160.1 to 104.5.175.254104.5.175.2554,094
92104.5.176.0/20104.5.176.1 to 104.5.191.254104.5.191.2554,094
93104.5.192.0/20104.5.192.1 to 104.5.207.254104.5.207.2554,094
94104.5.208.0/20104.5.208.1 to 104.5.223.254104.5.223.2554,094
95104.5.224.0/20104.5.224.1 to 104.5.239.254104.5.239.2554,094
96104.5.240.0/20104.5.240.1 to 104.5.255.254104.5.255.2554,094
97104.6.0.0/20104.6.0.1 to 104.6.15.254104.6.15.2554,094
98104.6.16.0/20104.6.16.1 to 104.6.31.254104.6.31.2554,094
99104.6.32.0/20104.6.32.1 to 104.6.47.254104.6.47.2554,094
100104.6.48.0/20104.6.48.1 to 104.6.63.254104.6.63.2554,094
101104.6.64.0/20104.6.64.1 to 104.6.79.254104.6.79.2554,094
102104.6.80.0/20104.6.80.1 to 104.6.95.254104.6.95.2554,094
103104.6.96.0/20104.6.96.1 to 104.6.111.254104.6.111.2554,094
104104.6.112.0/20104.6.112.1 to 104.6.127.254104.6.127.2554,094
105104.6.128.0/20104.6.128.1 to 104.6.143.254104.6.143.2554,094
106104.6.144.0/20104.6.144.1 to 104.6.159.254104.6.159.2554,094
107104.6.160.0/20104.6.160.1 to 104.6.175.254104.6.175.2554,094
108104.6.176.0/20104.6.176.1 to 104.6.191.254104.6.191.2554,094
109104.6.192.0/20104.6.192.1 to 104.6.207.254104.6.207.2554,094
110104.6.208.0/20104.6.208.1 to 104.6.223.254104.6.223.2554,094
111104.6.224.0/20104.6.224.1 to 104.6.239.254104.6.239.2554,094
112104.6.240.0/20104.6.240.1 to 104.6.255.254104.6.255.2554,094
113104.7.0.0/20104.7.0.1 to 104.7.15.254104.7.15.2554,094
114104.7.16.0/20104.7.16.1 to 104.7.31.254104.7.31.2554,094
115104.7.32.0/20104.7.32.1 to 104.7.47.254104.7.47.2554,094
116104.7.48.0/20104.7.48.1 to 104.7.63.254104.7.63.2554,094
117104.7.64.0/20104.7.64.1 to 104.7.79.254104.7.79.2554,094
118104.7.80.0/20104.7.80.1 to 104.7.95.254104.7.95.2554,094
119104.7.96.0/20104.7.96.1 to 104.7.111.254104.7.111.2554,094
120104.7.112.0/20104.7.112.1 to 104.7.127.254104.7.127.2554,094
121104.7.128.0/20104.7.128.1 to 104.7.143.254104.7.143.2554,094
122104.7.144.0/20104.7.144.1 to 104.7.159.254104.7.159.2554,094
123104.7.160.0/20104.7.160.1 to 104.7.175.254104.7.175.2554,094
124104.7.176.0/20104.7.176.1 to 104.7.191.254104.7.191.2554,094
125104.7.192.0/20104.7.192.1 to 104.7.207.254104.7.207.2554,094
126104.7.208.0/20104.7.208.1 to 104.7.223.254104.7.223.2554,094
127104.7.224.0/20104.7.224.1 to 104.7.239.254104.7.239.2554,094
128104.7.240.0/20104.7.240.1 to 104.7.255.254104.7.255.2554,094
129104.8.0.0/20104.8.0.1 to 104.8.15.254104.8.15.2554,094
130104.8.16.0/20104.8.16.1 to 104.8.31.254104.8.31.2554,094
131104.8.32.0/20104.8.32.1 to 104.8.47.254104.8.47.2554,094
132104.8.48.0/20104.8.48.1 to 104.8.63.254104.8.63.2554,094
133104.8.64.0/20104.8.64.1 to 104.8.79.254104.8.79.2554,094
134104.8.80.0/20104.8.80.1 to 104.8.95.254104.8.95.2554,094
135104.8.96.0/20104.8.96.1 to 104.8.111.254104.8.111.2554,094
136104.8.112.0/20104.8.112.1 to 104.8.127.254104.8.127.2554,094
137104.8.128.0/20104.8.128.1 to 104.8.143.254104.8.143.2554,094
138104.8.144.0/20104.8.144.1 to 104.8.159.254104.8.159.2554,094
139104.8.160.0/20104.8.160.1 to 104.8.175.254104.8.175.2554,094
140104.8.176.0/20104.8.176.1 to 104.8.191.254104.8.191.2554,094
141104.8.192.0/20104.8.192.1 to 104.8.207.254104.8.207.2554,094
142104.8.208.0/20104.8.208.1 to 104.8.223.254104.8.223.2554,094
143104.8.224.0/20104.8.224.1 to 104.8.239.254104.8.239.2554,094
144104.8.240.0/20104.8.240.1 to 104.8.255.254104.8.255.2554,094
145104.9.0.0/20104.9.0.1 to 104.9.15.254104.9.15.2554,094
146104.9.16.0/20104.9.16.1 to 104.9.31.254104.9.31.2554,094
147104.9.32.0/20104.9.32.1 to 104.9.47.254104.9.47.2554,094
148104.9.48.0/20104.9.48.1 to 104.9.63.254104.9.63.2554,094
149104.9.64.0/20104.9.64.1 to 104.9.79.254104.9.79.2554,094
150104.9.80.0/20104.9.80.1 to 104.9.95.254104.9.95.2554,094
151104.9.96.0/20104.9.96.1 to 104.9.111.254104.9.111.2554,094
152104.9.112.0/20104.9.112.1 to 104.9.127.254104.9.127.2554,094
153104.9.128.0/20104.9.128.1 to 104.9.143.254104.9.143.2554,094
154104.9.144.0/20104.9.144.1 to 104.9.159.254104.9.159.2554,094
155104.9.160.0/20104.9.160.1 to 104.9.175.254104.9.175.2554,094
156104.9.176.0/20104.9.176.1 to 104.9.191.254104.9.191.2554,094
157104.9.192.0/20104.9.192.1 to 104.9.207.254104.9.207.2554,094
158104.9.208.0/20104.9.208.1 to 104.9.223.254104.9.223.2554,094
159104.9.224.0/20104.9.224.1 to 104.9.239.254104.9.239.2554,094
160104.9.240.0/20104.9.240.1 to 104.9.255.254104.9.255.2554,094
161104.10.0.0/20104.10.0.1 to 104.10.15.254104.10.15.2554,094
162104.10.16.0/20104.10.16.1 to 104.10.31.254104.10.31.2554,094
163104.10.32.0/20104.10.32.1 to 104.10.47.254104.10.47.2554,094
164104.10.48.0/20104.10.48.1 to 104.10.63.254104.10.63.2554,094
165104.10.64.0/20104.10.64.1 to 104.10.79.254104.10.79.2554,094
166104.10.80.0/20104.10.80.1 to 104.10.95.254104.10.95.2554,094
167104.10.96.0/20104.10.96.1 to 104.10.111.254104.10.111.2554,094
168104.10.112.0/20104.10.112.1 to 104.10.127.254104.10.127.2554,094
169104.10.128.0/20104.10.128.1 to 104.10.143.254104.10.143.2554,094
170104.10.144.0/20104.10.144.1 to 104.10.159.254104.10.159.2554,094
171104.10.160.0/20104.10.160.1 to 104.10.175.254104.10.175.2554,094
172104.10.176.0/20104.10.176.1 to 104.10.191.254104.10.191.2554,094
173104.10.192.0/20104.10.192.1 to 104.10.207.254104.10.207.2554,094
174104.10.208.0/20104.10.208.1 to 104.10.223.254104.10.223.2554,094
175104.10.224.0/20104.10.224.1 to 104.10.239.254104.10.239.2554,094
176104.10.240.0/20104.10.240.1 to 104.10.255.254104.10.255.2554,094
177104.11.0.0/20104.11.0.1 to 104.11.15.254104.11.15.2554,094
178104.11.16.0/20104.11.16.1 to 104.11.31.254104.11.31.2554,094
179104.11.32.0/20104.11.32.1 to 104.11.47.254104.11.47.2554,094
180104.11.48.0/20104.11.48.1 to 104.11.63.254104.11.63.2554,094
181104.11.64.0/20104.11.64.1 to 104.11.79.254104.11.79.2554,094
182104.11.80.0/20104.11.80.1 to 104.11.95.254104.11.95.2554,094
183104.11.96.0/20104.11.96.1 to 104.11.111.254104.11.111.2554,094
184104.11.112.0/20104.11.112.1 to 104.11.127.254104.11.127.2554,094
185104.11.128.0/20104.11.128.1 to 104.11.143.254104.11.143.2554,094
186104.11.144.0/20104.11.144.1 to 104.11.159.254104.11.159.2554,094
187104.11.160.0/20104.11.160.1 to 104.11.175.254104.11.175.2554,094
188104.11.176.0/20104.11.176.1 to 104.11.191.254104.11.191.2554,094
189104.11.192.0/20104.11.192.1 to 104.11.207.254104.11.207.2554,094
190104.11.208.0/20104.11.208.1 to 104.11.223.254104.11.223.2554,094
191104.11.224.0/20104.11.224.1 to 104.11.239.254104.11.239.2554,094
192104.11.240.0/20104.11.240.1 to 104.11.255.254104.11.255.2554,094
193104.12.0.0/20104.12.0.1 to 104.12.15.254104.12.15.2554,094
194104.12.16.0/20104.12.16.1 to 104.12.31.254104.12.31.2554,094
195104.12.32.0/20104.12.32.1 to 104.12.47.254104.12.47.2554,094
196104.12.48.0/20104.12.48.1 to 104.12.63.254104.12.63.2554,094
197104.12.64.0/20104.12.64.1 to 104.12.79.254104.12.79.2554,094
198104.12.80.0/20104.12.80.1 to 104.12.95.254104.12.95.2554,094
199104.12.96.0/20104.12.96.1 to 104.12.111.254104.12.111.2554,094
200104.12.112.0/20104.12.112.1 to 104.12.127.254104.12.127.2554,094
201104.12.128.0/20104.12.128.1 to 104.12.143.254104.12.143.2554,094
202104.12.144.0/20104.12.144.1 to 104.12.159.254104.12.159.2554,094
203104.12.160.0/20104.12.160.1 to 104.12.175.254104.12.175.2554,094
204104.12.176.0/20104.12.176.1 to 104.12.191.254104.12.191.2554,094
205104.12.192.0/20104.12.192.1 to 104.12.207.254104.12.207.2554,094
206104.12.208.0/20104.12.208.1 to 104.12.223.254104.12.223.2554,094
207104.12.224.0/20104.12.224.1 to 104.12.239.254104.12.239.2554,094
208104.12.240.0/20104.12.240.1 to 104.12.255.254104.12.255.2554,094
209104.13.0.0/20104.13.0.1 to 104.13.15.254104.13.15.2554,094
210104.13.16.0/20104.13.16.1 to 104.13.31.254104.13.31.2554,094
211104.13.32.0/20104.13.32.1 to 104.13.47.254104.13.47.2554,094
212104.13.48.0/20104.13.48.1 to 104.13.63.254104.13.63.2554,094
213104.13.64.0/20104.13.64.1 to 104.13.79.254104.13.79.2554,094
214104.13.80.0/20104.13.80.1 to 104.13.95.254104.13.95.2554,094
215104.13.96.0/20104.13.96.1 to 104.13.111.254104.13.111.2554,094
216104.13.112.0/20104.13.112.1 to 104.13.127.254104.13.127.2554,094
217104.13.128.0/20104.13.128.1 to 104.13.143.254104.13.143.2554,094
218104.13.144.0/20104.13.144.1 to 104.13.159.254104.13.159.2554,094
219104.13.160.0/20104.13.160.1 to 104.13.175.254104.13.175.2554,094
220104.13.176.0/20104.13.176.1 to 104.13.191.254104.13.191.2554,094
221104.13.192.0/20104.13.192.1 to 104.13.207.254104.13.207.2554,094
222104.13.208.0/20104.13.208.1 to 104.13.223.254104.13.223.2554,094
223104.13.224.0/20104.13.224.1 to 104.13.239.254104.13.239.2554,094
224104.13.240.0/20104.13.240.1 to 104.13.255.254104.13.255.2554,094
225104.14.0.0/20104.14.0.1 to 104.14.15.254104.14.15.2554,094
226104.14.16.0/20104.14.16.1 to 104.14.31.254104.14.31.2554,094
227104.14.32.0/20104.14.32.1 to 104.14.47.254104.14.47.2554,094
228104.14.48.0/20104.14.48.1 to 104.14.63.254104.14.63.2554,094
229104.14.64.0/20104.14.64.1 to 104.14.79.254104.14.79.2554,094
230104.14.80.0/20104.14.80.1 to 104.14.95.254104.14.95.2554,094
231104.14.96.0/20104.14.96.1 to 104.14.111.254104.14.111.2554,094
232104.14.112.0/20104.14.112.1 to 104.14.127.254104.14.127.2554,094
233104.14.128.0/20104.14.128.1 to 104.14.143.254104.14.143.2554,094
234104.14.144.0/20104.14.144.1 to 104.14.159.254104.14.159.2554,094
235104.14.160.0/20104.14.160.1 to 104.14.175.254104.14.175.2554,094
236104.14.176.0/20104.14.176.1 to 104.14.191.254104.14.191.2554,094
237104.14.192.0/20104.14.192.1 to 104.14.207.254104.14.207.2554,094
238104.14.208.0/20104.14.208.1 to 104.14.223.254104.14.223.2554,094
239104.14.224.0/20104.14.224.1 to 104.14.239.254104.14.239.2554,094
240104.14.240.0/20104.14.240.1 to 104.14.255.254104.14.255.2554,094
241104.15.0.0/20104.15.0.1 to 104.15.15.254104.15.15.2554,094
242104.15.16.0/20104.15.16.1 to 104.15.31.254104.15.31.2554,094
243104.15.32.0/20104.15.32.1 to 104.15.47.254104.15.47.2554,094
244104.15.48.0/20104.15.48.1 to 104.15.63.254104.15.63.2554,094
245104.15.64.0/20104.15.64.1 to 104.15.79.254104.15.79.2554,094
246104.15.80.0/20104.15.80.1 to 104.15.95.254104.15.95.2554,094
247104.15.96.0/20104.15.96.1 to 104.15.111.254104.15.111.2554,094
248104.15.112.0/20104.15.112.1 to 104.15.127.254104.15.127.2554,094
249104.15.128.0/20104.15.128.1 to 104.15.143.254104.15.143.2554,094
250104.15.144.0/20104.15.144.1 to 104.15.159.254104.15.159.2554,094
251104.15.160.0/20104.15.160.1 to 104.15.175.254104.15.175.2554,094
252104.15.176.0/20104.15.176.1 to 104.15.191.254104.15.191.2554,094
253104.15.192.0/20104.15.192.1 to 104.15.207.254104.15.207.2554,094
254104.15.208.0/20104.15.208.1 to 104.15.223.254104.15.223.2554,094
255104.15.224.0/20104.15.224.1 to 104.15.239.254104.15.239.2554,094
256104.15.240.0/20104.15.240.1 to 104.15.255.254104.15.255.2554,094

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.